A control box that is surrounded on all sides by a shell is specified in DE295 19 260 U1. Such a cooling device which can be placed on the cover wall of the control box includes a roof element that, while connected to the upper side of the cooling device, projects beyond the cooling device housing on all sides.
As a rule, cooling devices such as the one disclosed in DE 37 10 566 C2, have an air inlet in the side wall for fresh air, and an air outlet for warmed exhaust air. The air inlet and air outlet are then covered by means of a ventilation screen. While such a ventilation screen is useful in preventing moisture and dirt particles from entering the air inlet once the cooling device is in operation, it offers no guarantee that moisture and dirt particles will not penetrate into the control box through the air conditioner while the control box and air conditioner are being set up in the field.